Portable scaffolds



Oct. 16, 1962 c. w. PRossER PORTABLE scAFFoLDs 5 Sheets-Sheet 2 FiledMarch 29. 1961 INVENTOR. CLYDE w. PROSSER BY M his ATTORNEYS Oct. 16,1962 c. w. PRossER 3,058,543

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. .I l, f' 35 INVENTOR 'Il Il Vl CLYDE w. PRossER f @d "li BY j Illu Maehis ATToR/vEl/s United States Patent O 3,558,543 PORTABLE SCAFFULDSClyde W. Prosser, 217 @riale Drive, Pittsburgh, Pa. Filed Mar. 29, 1961,Ser. No. 99,255 6 Claims. ('Cl. 182128) This invention relates toportable scaffolds and particularly to portable collapsible scaifoldsfor use in the interiors of vessels having variable internal dimensions.

The problem of removing and replacing the linings of bottle type vesselssuch as Bessemer converters, blast furnaces, LD. vessels, ladles and thelike has been complicated by the lack of a satisfactory scaffoldstructure. Such vessels ordinarily vary in diameter from top to bottomand in some cases may be small at the top, large intermediate the topand bottom and small again at the bottom. The blast furnace is typicalof such a structure. Other combinations of internal diameter may, ofcourse, be readily found when such variations in diameter occur; the topwork surface must, of course, vary in order that the workmen may beproperly positioned with respect to the wall surface being worked on.This creates a problem of proper cantilever construction in order tosupport the work surface at the large diameters and yet be in a positionto continue the scaffold to the smaller diameters. In the past,scaffolding such vessels for internal lining has been difhcult andexpensive because of the need to build continuous scaffolding, first toremove the old lining, then to remove the scaffold piece by piece as thelining is removed and then to start again at the bottom to rebuild thescaffold.

The foregoing problems have long been recognized but no reallysatisfactory scaffold has heretofore been proposed. It has been proposedto overcome this difficulty by suspending xa platform on ropes whichextend through the mouth of the vessel to a winch arrangement on asuperstructure over the vessel. Such a structure is shown in lordanPatent No. 2,346,033, assigned to Bethlehem Steel Corporation. Amodification of this structure is that of Putnam Patent No. 2,710,418.However, these scaffold structures require some `continuous suspensionmeans extending through the vessel mouth; they are much less stable thana bottom supported scaffold; the likelihood of accident is greater andthe upper Iworking surface is obstructed with support cables.

I have invented a scaffold structure which overcomes the aforementionedproblems and which is simple, inexpensive and readily portable.Preferably, I provide an unobstructed work platform with a base,telescoping cylindrical support members, one about the other, with thecylinder of smallest diameter fixed to the base, a top main frame on thetop of the cylinder of largest diameter, folding frame members on themain frame, flooring members removably on said frame, means for raisingthe cylinder successively and means for locking the bottom of onecylinder adjacent the top of the next inner cylinder.

In the foregoing general description, I have set out certain of theobjects, advantages and purposes of my invention; other objects,purposes and advantages will be apparent from a consideration of thefollowing description and the accompanying drawings in which,

FIGURE l is a vertical section through a furnace to be lined showing apreferred form of scaffold of my invention in lowest collapsed position;

FIGURE 2 is a vertical section of the furnace of FIG- URE l with thescaffold in partially raised position and extreme sections of platformremoved to reduce the diameter of platform;

FIGURE 3 is a vertical section of the furnace of FIG- URE 1 with thescaffold in fully extended position, removable sections of platformremoved and main floor beams folded at side of cylinder;

3,5,543 Patented Oct. 16, 1962 ICC 2 FIGURE 4 is a section on the lineIV-IV of FIGURE 1 FIGURE 5 is an enlarged segmental section on the lineV-V of FIGURE l and shows safety cage base in rst position;

FIGURE 6 is a segmental top plan view of the scaffold lift bararrangement;

FGURE 7 is a segmental section at the top and bottom of adjacentsegments showing the top and bottom rollers;

FIGURE 8 is a segmental section of the pawl and ratchet lift on the lineVIII-VIII of FIGURE 5';

FIGURE 9 is a section of the pawl and ratchet lift on the line IX-IX ofFIGURE 5;

FIGURE 10a is an enlarged segmental section through the walls of thehollow members showing the removable base bracket in second position;

FIGURE 10b is an enlarged segmental section through the walls of thehollow members showing the removable base brackets in a fourth position.

Referring to the drawings, I have illustrated a furnace 10 to be linedhaving a main body portion and a tapered neck. A scaffold base 11 isadapted to rest on the bottom of the furnace and is provided withradially extensible stabilizing arms 12 pivoted on posts 13 fixed to thebase. The base is of a diameter 4small enough to enter the opening 14 atthe end of the tapered neck. A plurality of cylinders 15, 16, 17, 1'8and 19 held together by a series of removable pins 22a and telescopingone about the other are nested on the base 11. The larger cylinder 19 isprovided with a lift bar 2o to receive a crane 2.1 whereby the entireunit may be inserted into the furnace and extended in the furnace. Eachof the cylinders 15 through 19 are provided at top and bottom withcooperating openings 22 (top) and 23 (bottom) through which lock pins23a may be inserted from the interior of the cylinders to hold thecylinders in extended position. The top of the outer cylinder 19 isprovided with sixteen pairs ofY hinged arms 24 and 25 of differentlengths, all adapted to fold against the sides of the cylinder. Whenextended these arms are adapted to receive removable gratings 26 and 26aand 2Gb which serve as a work surface. The length of short arms 25 isdetermined by diameter of platform at highest work level. The long arms24 are provided with hinged end pieces 24a which may be pivoted down tothe position shown in chain line in FIGURE 5.

When it is desired to use the scaffold the entire assembly is loweredthrough the opening 1'4 in the top of the furnace by crane hook 21. Thestabilizing arms 12 are extended to engage the outer walls of thefurnace. Arms 2d are raised to their extended position, pinned in placewith knee braces Mb, and removable gratings 26, 26a and 26h are placedthereon. Stabilizers 24C are placed at platform level to bear againstthe furnace walls with rollers 24d. When it is necessary to raise thescaffold the hook 21 is lowered to engage lift bar Ztl, the topstabilizers 24e released, the 4-pins 22a are removed, and the nestedcylinders are raised until the opening 22 in the top of the bottomcylinder and the opening 23v in the bottom of the next to bottomcylinder are approximately in alignment. The openings 22 are broughtinto precise alignment by hydraulic jack 27 mounted on top of a rack 2Sslidable in a carrier Z9 carrying a pinion 30 in engagement with rack28. The pinion 30 is on shaft 31a carrying a toothed ratchet wheel 32engaged by a pawl 32a on the carrier 25a. When the openings 22 and 23are aligned, the lock pins 23 are inserted. The lock pins are insertedfrom a safety cage 33 suspended in the center of the top cylinder andentered by a hinged cover 34 in the top grating. In order to facilitatemovement of the several cylinders with respect to one another rollers 35are provided on the bottom of each cylinder engaging the outer wall ofthe next smaller cylinder and rollers 36 are provided at the top of eachexternal wall of each cylinder to bear on the inner wall of the nextlarger cylinder. This is repeated until the taper portion of theinterior is reached. At this point the hinged ends 24a of the long arms24 are dropped to a vertical position as shown in chain line in FIGUREgratings 26h are removed from the vessel. To extend work platform to topposition the long arms 24 are dropped to side of top cyilnder andgratings 24h are removed from vessel.

The bottom of the carrier 29 is mounted on a beam 37 carrying the baseof cage 30. A hand winch 38 mounted on carrier 29 in cage 30 is providedwith a cable 38a reeved over a sheave 39 on the lift bar 20 andconnected to a clevis 37b on beam 37. A-fter the pins 23 have beeninserted to complete a raised section of the scaffold the beam 37 andwith it oor of cage 30 is raised a distance substantially equal to thelast rise in the scaiold and beam 37 is held by a removable bracket 40inserted in holes 40a and 4Gb in the side wall of the cylinder nextbelow the last one elevated.

In the foregoing specification I have set out certain preferredembodiments of my invention. It will be understood, however, that thisinvention may be otherwise embodied within the scope of the followingclaims.

I claim: v

l. A portable scalfold particularly adapted for use in vessels having anopening smaller than the interior diameter comprising a base adapted topass through said opening, a plurality of hollow elongated memberstelescoping within one another, cooperating lock means on the top andbottom of each said member adapted to hold the bottom of one memberadjacent the top of the next smaller Vmember in extensible position,support arms hinged at the top of the largest member adapted to beraised to the horizontal position and held there, removable gratingmeans on said arms, rack means axially of s aid hollow elongated memberssuspended from the top member, adjustable beam means on the bottom ofsaid rack selectively attachable to each member and jack means in therack means whereby the top member may be adjustably positioned withrespect to the other hollow members.

2. A portable scaffold particularly adapted for use in vessels having anopening smaller than the interior diameter comprising a base adapted topass through said opening, a plurality of hollow elongated members telescoping within one another, a lift beam at the top of the largest ofsaid members, cooperating lock means on the top and bottom of each saidmember adapted to hold the bottom of one member adjacent the top of thenext smaller member in extensible position, support arms hinged at thetop of the largest member adapted to be raised to the horizontalposition, locking means to hold said arms in the horizontal position,jack means suspended beneath the lift beam, rack means on the jack meansextending axially of the hollow members, a guide tube reciprocable onthe rack means, a pinion operably engaging the rack and held in positionby a pawl and ratchet, adjustable base means on the guide tubeselectively attachable to the interior of each hollow member and hoistmeans on the guide tube connected to the lift beam for lifting theadjustable base means and removable grating means on the arms forming aworking platform.

3. A portable scaffold as claimed in claim 2 wherein the base means isheld in removable brackets on the inlterior of each of the hollowmembers.

4. A portable scaiold as claimed in claim 2 wherein the hoist means is awinch on the guide tube having a cable passing over a sheave on the liftbeam and anchored to the base means.

5. A portable scaffold as claimed in claim 2 wherein `the support armsare spaced apart circumferentially of the largest member and are of twolengths, each having a removable stabilizer on the end thereof adaptedto bear against the interior of the vessel being worked upon.

6. A portable scaifold as claimed in claim 2 wherein stabilizer meansare attached to the base and adapted to bear against the interiorsidewalls of the vessel being worked upon.

References Cited in the le of this patent UNITED STATES PATENTS HopfeldAug. 9, 1960

